Energy conserving directional valve-cylinder combination

ABSTRACT

This invention relates to directional control valves designed to conserve fluid energy when serving power cylinders, and more particularly to an energy conserving TANDEM DIRECTIONAL VALVECYLINDER COMBINATION utilizing a solenoid valve of simple SPRINGLESS three component design to operate a specially designed power cylinder of differential diameter piston allowing the pressurized fluid to energize the piston of smaller area to do work and to return this piston to the original position by the exhaust of the same working fluid when work is completed, acting over the larger piston area in tandem action with pressurized working fluid passing through the passages of the directional control valve allowing for energy conservation with resultant savings to the user of such unit in automation, instrumentation and miniaturization fields.

United States Patent 1 1 Pauliukonis July 23, 1974 ENERGY CONSERVING DIRECTIONAL VALVE-CYLINDER COMBINATION [76] Inventor: Richard S. Pauliukonis, 6660 Greenbriar Dr., Cleveland, Ohio 22 Filed: Apr. 12, 1972 21 Appl. No.2 243,171

Primary EicaminerPaul E. Maslousky SUPPLY [57] V ABSTRACT This invention relates to directional control valves designed to conserve fluid energy when serving power cylinders, and more particularly to an energy conserving TANDEM DIRECTIONAL VALVE-CYLINDER COMBINATION utilizing a solenoid valve of simple SPRINGLESS three component design to operate a specially designed power cylinder of differential diameter piston allowing the pressurized fluid to energize the piston of smaller area to do work and to return this piston to the original position by the exhaust of the same working fluid when work is completed, acting over the larger piston area in tandem action with pressurized working fluid passing through the passages of the directional control valve allowing for energy conservation with resultant savings to the user of such unit in automation, instrumentation and miniaturization fields.

6 Claims, 5 Drawing Figures PATENTEDJIIL23I974 3.824.898

smell or 2 SUiPLY' v I ENERGY CONSERVING DIRECTIONAL VALVE-CYLINDER COMBINATION fluidto the outside.

continue in tandem flow to energize and feed the second cylinder at will until final exhaustof the working In' another application this tandem valve has successfully operated a double acting cylinder. But, rather than the pressurized fluid doingthe work, the exhaust fluid moved the piston forward in the conventional cylinder under reduced load. It should be noted here, that The two-way or three-way or four-way valves may be of manual or solenoid types. Generally athree-way valve serving a single acting cylinder, which is normally returned by a spring to the original position after the valve is opened to exhaust requires the working fluid to overcomespring resistance'in addition to the work load designated for each cylinder, with spring resistance force representing a sizeable energy requirement. Further, the use of a spring in a cylinder requires extra length of cylinder body which in double acting cylinders is not needed. Obviously, devices that would not require springs, andcould not utilize exhaust of the working fluidto replace the double acting cylinder function, with a single input of the working fluid are needed.

A four-way valve serving doubleacting cylinders as a rule is more complicated. In many a case the use of a four-way valve causes cylinder deterioration prematurely, imparticular if the application callsfor unidirecis passed over to the user at the expense of ignorance as the reducers are inefficient.

It is therefore the object'of the present invention. to improve operation of both the three-way valve serving a single acting-spring return cylinder which necessitates extra material'for cylinder body length, the spring itself and energy addition. all of which can be rather costly, although unavoidable within existing state of the art, and of the four-way serving a double acting cylinder with drastically improved efficiency and extended service duration due to innovation offered by this invention.

It is further object of this invention to provide a directional control valve designed to conserve fluid energy when serving power cylinders in valve-cylinder combination.

In one application this type of tandem directional valve has successfully operated two single acting-spring return cylinders in series, with the exhaust of the first cylinder feeding and actuating the second cylinder when solenoid was energized, and finally escaping to the outside via an exhaust port after returning second cylinder to the first position-deenergized, while the first cylinder became fully energized the moment the solenoid was deenergized, all by the pressurized working fluid that entered the normally open first cylinder to the accepted practice to do the work is. by pushing the piston-rod under load forward with the full force of the pressurized working fluid. In the application being discussed here in which a conventional cylinder was employed in conjunction with the tandem valve cited, more efficient performance and greater work could have resulted by way of piston retraction rather than forward push, because the designof the conventional cylinder with piston area larger at blind end does not lend itself to be controlled by this tandem valve, and to do work by a forward motion, unless the cylinder com ponents such as piston & rod assembly were redesigned, as proposed by this invention.

In applications such as reciprocating pumps that employ power cylinder-piston rods for displacement of fluids underload when energized by pneumatic/hydraulic working fluids, the piston is required to move forward under load opposed by the pumping fluid force, or being moved by the pressurized working fluid to extend under load rather than retract: the retraction of thepiston rod in such pumps is not associated with useful work, and normally needs little force for the position change of the piston-rod assembly to the retracte d first piston-rodposition, and subsequent push and extensionof the rod to the second position for performing the useful work of pumping. Obviously this tandem valve could be used successfully to do the pulling work by retracting piston rod of a conventional power cylinder in some applications where no forward load needs to be considered, but such applications are rather few. Rare are the applications cited above but while illustrating versatility of tandem valve, they show applications with push forward under load and retract the' piston-rod assembly under reduced load w/less force, or vice-versa.

The principal object of this invention is therefore to provide a valve-cylinder combinationthat would be capable of performing a useful forward motion under load resulting in work with maximum force of the working fluid under pressure entering such a directional valve during the normally open valve position for cylinder actuation, and subsequent return of the cylinder exhaust back into the valve for an external retraction of the piston-rod at the end of such useful forward motion and work to the original position of the piston rod by the same working fluid in a sequence that provides not only great economical gains in energy utilization but also preserves the integrityof the power cylin der physically, as the return of the piston-rod to the original first position is not accompanied by the full force of the working fluid, common to a four-way valve actuation, but is gently returned by expanded fluid that does the piston or piston-rod return function, for free, by otherwise not utilized cylinder exhaust.

To do this operation most economically, it was necessary to redesign the conventional cylinder, and to provide a differential area NOVEL PISTON, in order to expose larger, areas of the piston to the lower exhaust pressure of the working fluid, that leaves cylinder after I 3 I the forward motion of the piston iscompleted, for piston return to the original position, with smaller piston area experiencing full pressure of the working fluid initially, via an inlet port of the valve in directcommuni- .cation with the cylinder-port facing smaller piston to do suchwork as is required, andin proportion-to the forces needed.for...the return of subject piston to the .original -first position, for the subsequent sequential pressurization, work and return cycle associated with double acting cylinde'rs, but by the use of the same .working fluidrpassing through the appropriate valve passages in tandem in this valve-cylinder combination.

. Although bothtlie tandem directional' valve and the unconventional power cylinder of this invention retain their certain specific individual generic characteristics relative totheir function individually, and as such each cost, withimproved quality because of a rather unique ized workingfluid from a source such asidentified by 11 to a receiver 31 such as power cylinder inlet end'6'l, through a conduit-indicated diagrammatically at'1'2, &

H representing normally open valve adaptedto control the fluid flow for cylinder feed and "exhausfiwhile conduit l3 'with directional arrows identifies flow of fluid away from the cylinder opposite end for exhaust simplification of this valve-cylinder combination, and a j drastic departure from the existing'stateof the art in designs of similar cylinder valve combinations presently marketed. Infact, this invention may be c'onsidered a breakthrough of the century in, fluid power equipment design, as there were many attempts'to conserve energy in such or similar. applications without I success before, and assuch has been a dream of many professionals-inventors in the past.

'Other objects andadvantages of this invention relative to both, the energyconserving tandem valve and the power cylinder 'ofqunconventional design, separately and in combination, will become more fully apparent as the description proceeds in accordance with the drawings in which:'

FIG. 14; isacross-section'al view of the valve, identifying basic design components of the valve, with valve normally open and valve stempositioned solas to allow the cylinder feed with the pressurized fluid from the supply source to the receiver, namely the power cylinder, causing piston-rod extension as illustrated diagrammatically in the cylinder connected to the valve, with valve exhaust open.

FIG. l-b identifies valve with position change of both the valve stem, shown in detail and illustrating cylinder support port closed while the cylinder exhaust port is open for tandem flow of thefluid along the valve body, and the retraction of the piston rod,iwhile valve exhaust is closed.

FIG. 1-0 is a partial cross section of stem end of FIGS. l-a & 1-b enlarged, I

FIG. 2 is a cross-sectional view of the power with differentialpiston area, and other details of importance and novelty identified with piston rod retracted,

comprising original first load free position of the piston-rod assembly and prior to its pressurization for the position change and work.

FIG. 3 identifies differential sembly separately.

Refering to the drawings and particularly to FIG. l-a we find adirectional tandem valve 1 receiving pressurdiameter piston-rod ascylinder 5 through the valve opening identified by arrow: at I4. Turning to the description of valve 1 in'rn'oredetail,

it is seen to include a central elongated housing member 12 having an-axially extending-cylindricalbore 3 therein. Bore 3 has'an enlarged annular portion 4*com- 'inunicating directly with inlet'port S which may be threaded. One end of bore 3 is further enlarged and threaded at 6 to receive a solenoid operator 7 at'the end of annular portion 4 of which the opposite end becomes reduced resulting in smaller diameter annular portion 8 in direct communication with cylinder feed end-perpendicular-port 9' which is-threadedfor a close and rigid mounting of the tandem valve to the clyinder 31 shown diagrammatically. Port 9feed small piston 46 of blind cylinder end. A tapered shoulder 10 separating annularpo'rtions8 and 4 of the bore 3 serves ideally as sealing shoulder means for closing fluid communication between inlet'port Sand cylinderfeed port 9. Past .the cylinder feed port 9 the reduced annular portion 8- of the bore 3 again increases in size resulting in an en- ,larged annular portion 15, including another tapered shoulder 16 that canideally serve as sealing shoulder means for'closing communication of theworking fluid between annular portions8 and .15, when'needed. The annulus 15 at the extreme bore end 3," opposite to the solenoid end, terminates with a large threaded end '17 to receive an end -cap 2l with appropriate seal 22 en tering counterbore- 18 provided in the end of opening 17. Bore 23 in theend cap 21 is the main'valve exhaust. Annulus 15 is provided'with a perpendicularly situated fluid exit port 19, which also may .bethreaded, for fluid communication with the opposite cylinder end 20 via conduit 13 for piston return to the original first position by expandedfluid working over larger piston area with force larger than the opposite force at the smaller piston end when the port 9 is exhausting.

It must be noted again that when port 9 is exhausting, in reality it is supplying fluid via annular portions, 8 and 15 to the port 19 for further flow via conduit 13 to enter cylinder end at 20 for piston return to the original position, and thus it is still performing work comprising the energy conservation subject to this invention. The

amount of the energy conservation is strictly dependent I of the package design, the sizes and strokes of both the cylinder and the valve, the differential piston area and the ultimate balance desired in terms of pressures,'

speed of operation and work loads with intent to extract as much energy as this package of valve-cylinder combination concept provides, in accordance with the equilibrium-relationship of P V P V and the areas of the piston design governing the overall performance of this unit. The important consideration must be given to the resistance forces :and frictional characteristics of the piston in either directiombut most importantin sizing differential area for piston return to the original 5 first position by the fluid leaving port9 for tandem flow via passages described with relatively low energy level. The critical component of this package is the valve stem, actuated by the solenoid to shift within the valve during the fluid directional distribution, and the seals which must provide for a leak-proof valve at each position that the stem must assume in the course of trouble free tandem directional valve-cylinder operation.

Returning to the description of valve 1, an elongated stem 24 received slidably the valve bore 3 has an enlarged piston head 25 at one end, and a round stem end 26 at the other stem end, opposite to the piston head 25. A counterbore 32 with a cross drilled hole 33 perpendicular to this counterbore in the stem end 26 may be employed for increasing fluid exhaust port means to the open, at the end of each-cycle, in the course of the operation of this tandem valve-cylinder combination.

In the center of the piston 25 head, facing solenoid cavity, there is a small diameter protrusion 34 with a small hole 35 centrally drilled down into the protruding extention, & further into the stem, to exit on the other side of the stem piston. head at 36, but before the first stem seal 28, for. the fluid communication between the supply port 5, and the solenoid cavity 37 when needed. Solenoid plunger 38, provided with elastomeric insert 39, normally keeps this small hole 35 closed by the force of a spring 40 comprising a part of the solenoid operator. An insert 41 at the other plunger end of the solenoid operator 7 serves as sealing means for solenoid cavity 37 by closing solenoid. exhaust port 42 should the solenoid become energized as may be the case during the valve operation when need arises to shift the valve stem for redirecting fluid flow, and a position change of the piston-rodfrom that identified in FIG. 1-a to that identified in FIG. l-b.

For the purpose of directing the flow within the valve body in tandem before and after energization of the solenoid operator 7, seals must be applied to the stem and secured permanently as follows: seal 27 must be placed over the piston head 25, to insure separation of the annulus 4 from the solenoid cavity 37 in order to position stem as desired to either be as indicated in FIG. 1-a or 1-b; seal 28 must be placed over the stem at separating fluid inlet port from port 9; seal 29 must be placed over the stem at shoulder .16 to seal off annular portion 8 from annulus 15, and a seal 30 must be located at the end of the stem 26 for sealing exhaust port 23 which in FIG. 1-a permits fluid exhaust, and in FIG. 1-!) keeps fluid exhaust port 23 closed permitting exhaust fluid from port 9 to complete the cycle of returning extended piston rod to the original retracted position as shown in FIG. 1-b, before exhausting into open as shown in FIG. l-a. Its must be understood that FIG. l-a shows solenoid deenergized, and FIG. l-b identifies solenoid energized with the position change of the stern and of the cylinder in accordance with description of unit operation that follows. To note is the fact that in the design under consideration the shifting of the valve stem 24 by the working fluid is not affected by forces normally destructive in other designs with metal to metal contact, as in teh design under consideration all forces are absorbed by the elastomer seals strategically situated so as to absorb impact forces during the position change of the stem, and thus extending life duration of such valves manyfold, imparticular if such seals are made from materials with considerably larger strength and impact values, such as those found in urethane compounds of today. With piston head 25 inside annular portion 4 of bore 3 slidably moving along the elongated valve body 1 axially, while the 6. operation and the directional fluid flow within this valve according to needs is hereby insured.

I It should be pointed outthat the valve according to the present invention is particularly suitable for miniaturization, i.e. the valve is designed to be used as miniapiston-rod assembly. The differential area piston 44 has a small end 46 & a larger end 45 with rod 43 attached thereto, as shown in cylinder 31 with air vent 50. FIG.

1a shows normally open valve position with valve stem location permitting direct fluid communication under pressure into the cylinder port provided with smaller diameter piston 46 for piston forward motion and subsequent conversion of the fluid pressure energy into a linear motion as manifested by the extention of the piston rod under load while doing work, at which time the opposite cylinder end with large piston diameter is connected to the valve for exhaust, and the solenoid operator shown is deenergized, with its cavity open to atmosphere, i.e. to exhaust. Piston rod 43 of differential diameter piston 44 is in FIG. l-a extended, with working other extreme stem end 26 is guided inside bore 23, the

fluid filling void 49 created by displaced piston end 46, and resulting in an additional annular space 47 between piston & cylinder, vented through an air vent 50 to prevent air lock. Annular space 47 is acting as an atmospheric breather.

In FIG. 1-b the solenoid operator is energized for a quick influx and accumulation of the pressurized working fluid inside the solenoid cavity which is sealed off from the outside by the position change of the solenoid plunger, enabling a position change of the valve stem subjected to high working fluid pressure over piston head facing solenoid cavity, and subsequent shuttingoff of the pressurized fluid supply to the cylinder, with smaller diameter piston, while opening passages inside the valve to enable fluid exhaust from this cylinder with smaller diameter piston, previously under pressure, for communication with the opposite cylinder end provided with larger diameter piston, and retraction of the piston-rod to the original position-load free-by the action of exhausted fluid containing less energy when redirected and thus requiring larger piston area, for the necessary position change to repeat the cycle over and over, with the working fluid performing the double action function in the cylinder, by the use of the tandem directional valve of this invention, with great savings to the user. Piston rod 43 in FIG. l-b is retracted, identi fying pressure balance on both sides, not the force.

Of greatest significance to valve design is the fact that the preassembled stem with appropriate seals less one seal, permits an extremely easy valve assembly by sliding such preassembled stem through the solenoid port down into the valve body cavity until it reaches first sealing surface, by the first set of annular seals, and then becomes permanently secured by the last elastomer ring seal from the opposite valve end by the use of special proprietory tooling and method of operation in order to provide practically two component valve design, with characteristics of poppet valve in terms of speed of response, extremely large flow coefficient C,

within rather smalldimensional valve envelope and ease of maintenance, should it be needed. Adding endcap at the valve end makes this valve a simple three component springless valve design for operation which is strictly dependent on the pressurized fluid within the valve proper, and the solenoid operator to provide shifting of the stem for a troublefree operation of this valve. As such it meets the requirements of the valve of the future with simplicity, better quality and improved performance at less cost to the user. Because the stem is physically held inside the valve proper by the last ring-seal of elastomer origin which per se not only in-' volves novel means of valve construction but also acts as the energy absorber during the position change of the stem. It is believed that this design may substantiate the use. of elastomer, in Fluid Power field, to act as both as a seal and as a physical component, for competition withmetal retainers normally used for such purposes. However, since elastomer physical strength is lower than that of the metal, this valve will have to be limited as to the ultimate operating pressure it should serve. With urethane seal material exhibiting tensile properties of approximately 5,000 psi, and compressive strength of some compounds being quoted equally high, there is little doubt that these valves should outperform any counterpart-employ ing undesirable metal to metal contact designs, and equal in pressure rating all existing poppet valves, except for size which in the design subject to this'invention is considerably smaller 7 for equal flow coefficient C Another factor for consideration in solenoid valves, is the fact that in the energy conserving tandem directional valve, the solenoid is used as a pilot'unit for the purpose of shifting the stem only, without participation in fluid flow into and from the source to receiver, permitting valve design w/quite larger fluid passages and therefore larger flow characteristics, rarely found in poppet valves of such small size, capable of doing so large a work in terms of flow factor C regardless of system pressures normally controlling the operating capabilities of solenoids directly involved in valve operation. Therefore, the tandem directional valve can employ as small a solenoid as an be produced regardless of valve size, ports or C specified for a specific valve, and irrespective of system pressures, ,within limits, of course. The reason for the ability to yield such a high flow coefficient is rather obvious, namely the valve seals do not have to cross fluid perpendicular ports during the shift and position change of the stem, and thusno limits are present in terms of annular sizes that control such flow coefficients enabling this valve-cylinder combination to provide extremely large flows to speed up cylinder operation beyond that attainable with other valve designs in existance while the tandem valve size is miniature as compared to other designs in existance with equivalent flows at high pressures.

In FIG. l-c illustrating end of stem 26 of the longitudinal valve stem 24 in a position before entering valve exhaust bore 23 as shown in FIG. 1-a clearly illustrates ability available and proposed for increasing fluid exhaust means if desired. This can be accomplished by counterboring stem-end partway as shown by 32 and cross drilling holes 33 perpendicular to it & adjacent to the stem-end seal 30, with asmany holes 33 as it may deem tobe desired, although the operation of this valve with an exhaust annular space 47-a identified therein is insured without additional modification of thestem '8 end 26 in miniature valve applications of this valvecylinder combination of the invention.

FIG. 2 identifies cylinder with differential piston area.

As can be seen from FIG. 2, cylinder 31, with vent 50, of differential diameter cylindrical body 51 having end closure 52 integral with a smaller cylindrical portion 53 of the cylinder closed end 54,'and enlarged cylindrical portion 55 at the other open cylinder end 56 which is threaded, an end closure 57 with seal 58 closing cylinder open end seal tight, and a central opening 59 therein for a rod seal 60, isprovided with a differential diameter piston 44 with smaller diameter 46 facing, and adjacent to closure 52 while larger diameter piston end 45 facing closure 57 terminates with piston rod 43 passing thru the central opening 59 with seal 60 and, in the illustrated case is in a retracted piston rod position with annulus 47 open to atmosphere via vent 50. Port 61 leading to the smaller cylindrical portion 53 of cylin der 31 is provided for fluid communication from the fluid supply source under pressure as well as for fluid return via conduit 12 shown in FIGS. 1-0 and 1-12. Port 20 serves for entering fluid exhausted from other cylindirections as is the casein most double acting cylinder application. It must be noted that the cylinder 31 described above is sound and quite self-explanatory regarding the differential diameter cylinder and piston principle, and its applicational variations in the field of fluid power control, with drastic improvements in the state of the art, but in practice it would not pay to produce such devices as FIG. 2 illustrates. It would be not only difficult but too costly to make a differential diameter closed end cylinder from metal competitively. Also the differential diameter piston and piston rod assembly of FIG. 2 is prohibitive costwise to be produced from one piece. Such devices in practice are borken down to separate parts such as cylinder, rod end and blind end for a cylinder assembly of existing practice, and to piston and piston rod made separately and then assembled to comprise a single unit normally involving piston rod threading into the piston and soldering such a joint, and then trueing it out because during soldering heat may distort parts, or otherwise making a cylinder assembly extremely costly, and in case under consideration, as shown in FIG. 2, such a cylinder would not become rather very popular because of cost to produce it. Therefore we propose that the cylinder as identified in FIG. 2 be modified for adaptation to mass production, part of which is illustrated in FIG. 3.

In FIG. 3, the construction of differential piston-rod assembly is accentuated in a great detail with piston 200 representing small end, and piston 201 representing large end, with rod 202 providing a practical solution to the differential piston-rod-assembly 203 of this invention. Such differential diameter piston-rod assembly may even be fabricated by the conventional means using steel or metal competitively, with rod section 204 serving as interconnecting link for differential diameter pistons. Thus, it has been demonstrated that the energy conserving valve-cylinder combination employing directional tandem valve accomplishes all stated objectives. Fabricating cylinder by conventional means or mass producing simplified designs from plastics by injection molding or making cylinders from composite materials may be the best answer.

Some changes may be made in the construction and arrangements of thedetails without departing from the real spirit and purpose of this invention, disclosed and claimed herein.

What is claimed is:

1. An energy conserving directional valve-cylinder combination comprising:

a fluid motor including a cylinder, having one cylinder end blind including fluid supply and exhaust means provided therein, and another cylinder end open and adaptable to be closed partially by a rod end closure, said rod end closure including fluid supply and exhaust means provided therein and a central piston rod opening with a seal, said cylinder means including internal diameter tubular portions of large and small coaxial diameters separated by i a shoulder substantially midway thereof, with said larger diameter portion initiating at the cylinder open end while said smaller diameter portion continuing inwardly from said shoulder until it meets said blind end provided with a closure, atmospheric vent means in said cylinder adjacent-said shoulder,

a differential diameter piston means including coaxial piston rod attached thereto and protruding from said cylinder rod end closure, said piston means having an elongated smaller diameter piston at one end and a short larger diameter piston with said rod at the other end slidably received inside said cylinder means with said small piston entering said small diameter cylinder portion and said larger piston entering said large diameter cylinder portion and capable of axial movement in response to pressurized fluid supplied thereto by shuttling within cylinder confines controlled by said rod end closure at one piston rod extended position and said cylinder shoulder at the other piston rod retracted position, seals in said pistons,

means for actuating said fluid motor to perform work by said piston rod when coupled to a load during said position change of said differential diameter piston means insidesaid clyinder means, said actuation caused by said pressurized working fluid entering and leaving said fluid supply and exhaust means at each cylinder end alternatingly feeding said one cylinder end while simultaneously exhausting said other cylinder end, or vice versa as controlled by a directional valve closely coupled with said cylinder and capable of being selectively controlled between a first valve open position wherein fluid communication is permitted between a source of the pressurized working fluid and said cylinder blind end for pressurization of said small diameter piston with full pressure urging said piston rod extension under load, and a second valve closed position allowing energy extraction from fluid exhausted from said cylinder blind end by redirecting said working fluid in tandem from said blind end toward said cylinder open end provided with said rod end closure for pressurization of said larger diameter piston urging said piston rod retraction under load,

said energy conserving tandem directional valve comprising a multiported longitudinal valve housing'having first and second ends interconnected by a bore extending therethrough, said bore having a first diameter portion adjacent said first end extending inwardly therefrom toward said second end, a second diameter portion adjacent said second end'extending inwardly therefrom toward said first end and a third diameter portion interconnecting the innermost ends of said first and second diameters, said first and second diameter portions having larger diameters than said third diameter portion, including shoulders at interconnection of said diameters with a first shoulder facing said housing first end and a second shoulder facing said housing second end, said housing further including at least three perpendicular ports extending through said housing and communicating with said bore extending therethrough, one of said ports comprising a first fluid supply port communicating with said first diameter portion adjacent said first housing end and adaptable to be connected to said working fluid source, another of said ports comprising a second fluid port communicating with said third diameter portion and adaptable to be connected to said cylinder blind end, the remaining port comprising a third fluid port communicating with said second diameter portion adjacent said second housing end and adaptable to be connected to said fluid supply and exhaust means of said rod end closure covering said cylinder open end, said second bore end closedby an end cap provided with a central opening therethrough comprising a main valve exhaust port, said second and said third ports interconnected with said cylinder,

said first bore end receiving slidably an elongated stem with a piston at one end and a counterbored smaller diameter portion at the other end, said pis ton having a close sliding fit with the housing and having a seal received slidably inside said first diameter portion with piston head including an end face, a second seal in said stem received inside said first diameter portion and spaced along said stem from said piston adjacent said first shoulder with seal diameter less than the diameter of said piston but greater than said third diameter portion, a third seal in said stem having a diameter greater than said third diameter portion but less than said second diameter portion and located on a stem diameter portion received in said second diameter portion adjacent said second shoulder, a final seal on said opposite stem end adjacent said counterbored portion sized to permit close sliding fit inside said exhaust port of said end cap,

said stem being selectively shifted between a first position wherein said fluid communication is permitted between said first and second ports but precluded from entering said third port by said third seal firmly seated against said second shoulder while simultaneously allowing fluid communication between said third and said exhaust ports, and a second position wherein fluid communication is permitted between said second and third ports while having said second seal firmly seated against said first shoulder to preclude fluid communication between said first and second ports and also having said final seal engaged inside said main valve exhaust port to preclude fluid exhaust into the atmosphere, said stem further including a small fluid passage extending therethrough from said piston face for selectively allowing fluid flow from said first diameter portion through said fluid passage and outwardly from said end face, said second port connected to said fluid supply and exhaust means of said cylinder blind end and said third port to said cylinder rod end closure supply and exhaust means,

solenoid valve operator disposed at said first bore end of said housing, said operator having a plunger disposed generally coaxial with said stem and axially movable selectively in an operative relationship with solenoid energization between an open position spaced from said end face of said piston and defining a fluid cavity therebetween and a closed position in blockinglengagement with said small passage at said end face, wherein when said plungeris in said closed position saidstem is retained in said first position by fluid entering a first annulus formed between said stem and said first diameter portion provided with piston side, opposite said piston face end, exposed to said fluid with a force large enough to maintain said third sealfirmly seated against said second shoulder when said stem is in said first position with said valve open to full pressure of the working fluid feeding said cylinder blind end via said second port to urge said piston .rod into extended position while said main valve exhaust port is open to atmosphere, and wherein when said plunger is in said open position said stem is shifted to said second valve closed position by fluid entering said cavity through said passage in said piston end face and acting against said piston head exposed to said cavity with a force large enough to maintain said second seal firmly seated against said first shoulder while allowing pressurization of said cylinder open end provided with said rod end closure via said third port in communication with said second port through second and third annuluses formed between said second and third diameter portions and said stem by the fluid exhausted from said blind cylinder end to urge said piston rod into retracted position through the fluid action over said larger diameter piston,

said solenoid valve operator further including means for exhausting fluid from said cavity as said plunger is moved from said open toward said closed position, including spring biasing means for continuously exerting a biasing force on said plunger to force said plunger toward said closed position,

whereby when said solenoid valve operator is deenergized said spring biasing means forces said plunger from said open into said closed position,

12 energization of said solenoid causing said plunger to overcome said biasing force of said biasing means in moving from said closed to said open position.

2. A valve-cylinder combination as in claim 1 wherein said stem seals include tubular sections of elastomer rings.

3. A valve-cylinder combination as defined in claim 1 wherein said conservation of energy includes the utilization of tandem flow of pressurized fluid through said tandem directional valve, initiating at said fluid supply first port receiving pressurized fluid from the source and continuing into said second port to serve said cylinder bind end, and returning to said second fluid port to enter said third fluid port to serve said cylinder open end provided with said rod end closure, and

again returning to said third fluid port for final exhaust into the atmosphere via said main valve exhaust port,

said tandem fluid flowenabling extraction of useful pressure energy in compliance with the equilibrium energy equation expressed by the relationship RV, P V said relationship enabling the operation of said valve-cylinder combination with resultant significant conservation of energy, said relationship effective when combined with piston areas at each cylinder end.

4. A valve-cylinder combination as in claim 1 wherein said differential diameter piston means includes a plain rod with said small diameter piston of short length at one end and said larger diameter piston of short length positioned a distance away from said small diameter piston along said rod in accordance with cylinder stroke requirements, with said rod extending therethrough.

5. A device as in claim 1 wherein when said stem, subjected to the working fluid pressure, is forced to change said position from said first valve open position to said second valve closed position, said working fluid pressure end thrust force is absorbed by said stem seals, materially extending the service life of said tandem directional valve, said second and said third stem seals absorbing all impact forces developed during said stem position change.

6. A device as in claim 1 wherein said solenoid operator is used as a pilot unit solely for purpose of shifting said stern without direct participation in the flow of the working fluid through said valve permitting the utilization of considerably larger fluid flow passages therethrough, and permitting the use of as small a solenoid as available irrespective of the magnitude of the work- 

1. An energy conserving directional valve-cylinder combination comprising: a fluid motor including a cylinder, having one cylinder end blind including fluid supply and exhaust means provided therein, and another cylinder end open and adaptable to be closed partially by a rod end closure, said rod end closure including fluid supply and exhaust means provided therein and a central piston rod opening with a seal, said cylinder means including internal diameter tubular portions of large and small coaxial diameters separated by a shoulder substantially midway thereof, with said larger diameter portion initiating at the cylinder open end while said smaller diameter portion continuing inwardly from said shoulder until it meets said blind end provided with a closure, atmospheric vent means in said cylinder adjacent said shoulder, a differential diameter piston means including coaxial piston rod attached thereto and protruding from said cylinder rod end closure, said piston means having an elongated smaller diameter piston at one end and a short larger diameter piston with said rod at the other end slidably received inside said cylinder means with said small piston entering said small diameter cylinder portion and said larger piston entering said large diameter cylinder portion and capable of axial movement in response to pressurized fluid supplied thereto by shuttling within cylinder confines controlled by said rod end closure at one piston rod extended position and said cylinder shoulder at the other piston rod retracted position, seals in said pistons, means for actuating said fluid motor to perform work by said piston rod when coupled to a load during said position change of said differential diameter piston means inside said clyinder means, said actuation caused by said pressurized working fluid entering and leaving said fluid supply and exhaust means at each cylinder end alternatingly feeding said one cylinder end while simultaneously exhausting said otheR cylinder end, or vice versa as controlled by a directional valve closely coupled with said cylinder and capable of being selectively controlled between a first valve open position wherein fluid communication is permitted between a source of the pressurized working fluid and said cylinder blind end for pressurization of said small diameter piston with full pressure urging said piston rod extension under load, and a second valve closed position allowing energy extraction from fluid exhausted from said cylinder blind end by redirecting said working fluid in tandem from said blind end toward said cylinder open end provided with said rod end closure for pressurization of said larger diameter piston urging said piston rod retraction under load, said energy conserving tandem directional valve comprising a multiported longitudinal valve housing having first and second ends interconnected by a bore extending therethrough, said bore having a first diameter portion adjacent said first end extending inwardly therefrom toward said second end, a second diameter portion adjacent said second end extending inwardly therefrom toward said first end and a third diameter portion interconnecting the innermost ends of said first and second diameters, said first and second diameter portions having larger diameters than said third diameter portion, including shoulders at interconnection of said diameters with a first shoulder facing said housing first end and a second shoulder facing said housing second end, said housing further including at least three perpendicular ports extending through said housing and communicating with said bore extending therethrough, one of said ports comprising a first fluid supply port communicating with said first diameter portion adjacent said first housing end and adaptable to be connected to said working fluid source, another of said ports comprising a second fluid port communicating with said third diameter portion and adaptable to be connected to said cylinder blind end, the remaining port comprising a third fluid port communicating with said second diameter portion adjacent said second housing end and adaptable to be connected to said fluid supply and exhaust means of said rod end closure covering said cylinder open end, said second bore end closed by an end cap provided with a central opening therethrough comprising a main valve exhaust port, said second and said third ports interconnected with said cylinder, said first bore end receiving slidably an elongated stem with a piston at one end and a counterbored smaller diameter portion at the other end, said piston having a close sliding fit with the housing and having a seal received slidably inside said first diameter portion with piston head including an end face, a second seal in said stem received inside said first diameter portion and spaced along said stem from said piston adjacent said first shoulder with seal diameter less than the diameter of said piston but greater than said third diameter portion, a third seal in said stem having a diameter greater than said third diameter portion but less than said second diameter portion and located on a stem diameter portion received in said second diameter portion adjacent said second shoulder, a final seal on said opposite stem end adjacent said counterbored portion sized to permit close sliding fit inside said exhaust port of said end cap, said stem being selectively shifted between a first position wherein said fluid communication is permitted between said first and second ports but precluded from entering said third port by said third seal firmly seated against said second shoulder while simultaneously allowing fluid communication between said third and said exhaust ports, and a second position wherein fluid communication is permitted between said second and third ports while having said second seal firmly seated against said first shoulder to preclude fluid communication between said first and second ports and also having said final seal engaged inside Said main valve exhaust port to preclude fluid exhaust into the atmosphere, said stem further including a small fluid passage extending therethrough from said piston face for selectively allowing fluid flow from said first diameter portion through said fluid passage and outwardly from said end face, said second port connected to said fluid supply and exhaust means of said cylinder blind end and said third port to said cylinder rod end closure supply and exhaust means, a solenoid valve operator disposed at said first bore end of said housing, said operator having a plunger disposed generally coaxial with said stem and axially movable selectively in an operative relationship with solenoid energization between an open position spaced from said end face of said piston and defining a fluid cavity therebetween and a closed position in blocking engagement with said small passage at said end face, wherein when said plunger is in said closed position said stem is retained in said first position by fluid entering a first annulus formed between said stem and said first diameter portion provided with piston side, opposite said piston face end, exposed to said fluid with a force large enough to maintain said third seal firmly seated against said second shoulder when said stem is in said first position with said valve open to full pressure of the working fluid feeding said cylinder blind end via said second port to urge said piston rod into extended position while said main valve exhaust port is open to atmosphere, and wherein when said plunger is in said open position said stem is shifted to said second valve closed position by fluid entering said cavity through said passage in said piston end face and acting against said piston head exposed to said cavity with a force large enough to maintain said second seal firmly seated against said first shoulder while allowing
 2. A valve-cylinder combination as in claim 1 wherein said stem seals include tubular sections of elastomer rings.
 3. A valve-cylinder combination as defined in claim 1 wherein said conservation of energy includes the utilization of tandem flow of pressurized fluid through said tandem directional valve, initiating at said fluid supply first port receiving pressurized fluid from the source and continuing into said second port to serve said cylinder bind end, and returning to said second fluid port to enter said third fluid port to serve said cylinder open end provided with said rod end closure, and again returning to said third fluid port for final exhaust into the atmosphere via said main valve exhaust port, said tandem fluid flow enabling extraction of useful pressure energy in compliance with the equilibrium energy equation expressed by the relationship P1V1 P2V2, said relationship enabling the operation of said valve-cylinder combination with resultant significant conservation of energy, said relationship effective when combined with piston areas at each cylinder end.
 4. A valve-cylinder combination as in claim 1 wherein said differential diameter piston means includes a plain rod with said small diameter piston of short length at one end and said larger diameter piston of short length positioned a distance away from said small diameter piston along said rod in accordance with cylinder stroke requirements, with said rod extending therethrough.
 5. A device as in claim 1 wherein when said stem, subjected to the working fluid pressure, is forced to change said position from said first valve open position to said second valve closed position, said working fluid pressure end thrust force is absorbed by said stem seals, materially extending the service life of said tandem directional valve, said second and said third stem seals absorbing all impact forces developed during said stem position change.
 6. A device as in claim 1 wherein said solenoid operator is used as a pilot unit solely for purpose of shifting said stem without direct participation in the flow of the working fluid through said valve permitting the utilization of considerably larger fluid flow passages therethrough, and permitting the use of as small a solenoid as available irrespective of the magnitude of the working fluid pressure. 